Hitting a bump at speed can cause several problems:
Tire or wheel damage: generally this requires a replacement tire or wheel
Suspension damage: a suspension member could have been bent or damaged by the impact
Alignment problems: this isn't damage, just needs a re-alignment
Lost wheel balancing weights: this is easily fixed by getting the wheels re-...
Thanks for all the responses. We found the problem. I ordered the rear tires for the car that were the correct size...I didn't realize that they had an incorrect sized tire on the vehicle when I bought it. So I ended up with two different diameter tires on an AWD vehicle which I found out doesn't work. Apparently running different sized tires on AWD vehicles ...
Although the explanation as to why the system vibrates at wheel frequency instead of propshaft frequency is a bit of a mystery, I have tracked the source of the problem to the transmission itself having very badly worn bearings. The only remedy is to overhaul or replce the transmission.
High speed vibration on a FWD vehicle could be wheel bearings, but you've already replaced those. Mostly likely is bad wheels and/or tires. Out of balance, uneven road force, or a bent wheel could all cause high speed vibrations. Uneven road force means that the tire doesn't exert the same amount of pressure at all points around the tire (imagine if a ...